gpio: add Intel Moorestown Platform Langwell chip gpio driver

The Langwell chip is the IO hub for Intel Moorestown platform which has a
64-pin gpio block device inside.  It is exposed as a dedicated PCI device.
 We use it to control outside peripheral as well as to do IRQ demuxing.
The gpio block uses MSI to send level type interrupt to IOAPIC.

Signed-off-by: Alek Du <alek.du@intel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ccca08e..9ad20ff 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -180,6 +180,12 @@
 
 	  If unsure, say N.
 
+config GPIO_LANGWELL
+	bool "Intel Moorestown Platform Langwell GPIO support"
+	depends on PCI
+	help
+	  Say Y here to support Intel Moorestown platform GPIO.
+
 comment "SPI GPIO expanders:"
 
 config GPIO_MAX7301